NE
W
571 DBC
9.955.042 01
Subject to change without notice
ELECTRONIC BURNER CONTROL DEVICE
WITH MICROPROCESSOR FOR UNIVERSAL
USE IN GAS FIRED APPLICATIONS
Field of application
Main features
NG or LPG fired gas
appliances such as boilers
(with natural or forced
draught including dynamic
control of the air pressure
switch), water heaters,
hot air generators, tumble
driers gas radiators and
other gas-fired appliances.
Gas burner ignition managed
by digital technology
(microprocessor) with multiple
ignition attempts.
w
9955042_H00.indd 1
w
w
.
s
i
t
g
r
o
u
p
.
i
t
15/07/2009 16.29.38
571 DBC
DESCRIPTION AND APPLICATION
The 571 DBC control is a family of electronic ignition devices for gas-fired appliances.
All the functions are managed by a microprocessor and the product has obtained
the certification of conformity with the most severe safety requirements by both CSA
and European notified bodies. The microcontroller structure combines the traditional
features of high reliability with high flexibility for the needs of the appliance. The 571
DBC family of products have been specifically designed to be used in a wide variety
of gas-fired appliances. Any customization is easy to achieve thanks to the digital
technology. All the hardware and firmware architecture have been designed by SIT and
innovative concepts and technologically advanced solutions haven been implemented
so as to achieve the product’s best reliability and performances.
BASIC FEATURES
- Compact design
- Incorporated spark igniter with EMC filter or Hot Surface Igniter driver
- Direct burner ignition (DBI) or pilot valve
- Remote signalling of the lockout state
- Multiple plug-in connectors
- Utilises well established electronic technology for high reliability of operations
- Precise and repeatable timings
- Multiple ignition attempts
- Flame detection by ionization
- CSA approval and CE approval
- Repetition of the cycle after loss of flame during operation
- Suitable for applications at wide ambient temperature range
- ROHS compliant.
Options available
- Fan and air pressure switch control
- Non-volatile lockout version for specific applications
- Line voltage or optocoupled flame presence signal
- Different flame current sensitivity options may be specified
- Several pre-purge and safety timings can be tailored to the application.
- Different frequency of ignition
- Auto-reset function in case of flame loss or ignition problems after 1 hour
- With or without enclosure
2
9955042_H00.indd 2
15/07/2009 16.29.38
571 DBC
BOILERS WITH
NATURAL DRAUGHT
OPERATION
Normal operation (natural draught or fan assisted)
During the waiting or purge time, Tw or Tp, the unit verifies that there
is no parasitic flame signal present, and that the internal circuitry is
operating correctly. If the unit is used on a fan-assisted application, the
air pressure switch is verified to be in the N.C. (normally closed) or “no
flow” position.
Upon powering the fan, the unit will not begin the operating sequence
until the N.O. (normally open) or “flow” position is activated on the air
pressure switch. After the scheduled waiting time Tw, or purge time Tp,
the built-in igniter and the gas valve are energized. This commences the
safety time, Ts. The ignition spark will ignite the gas and the flame will
be sensed by the electrode.
If there is no flame the system repeats the ignition cycle, after a defined
interpurge time, for a definite number of times and it goes definitively
on lockout position in case there is no flame.
Upon sensing the flame, the HV spark will be suppressed and the gas
valve will remain energized. When the thermostat is open, the valve
and fan are de-energized and the control returns to the stand-by mode.
The safety time of the 571 DBC has a constant duration in all operating
conditions and, in particular, does not depend on the moment the
pressure switch is switched over.
Resetting the unit
To reset the unit the power has to be removed for at least one second
and then restored in case of volatile LO version.
In case of non-volatile version: close input 1 and 2 of connector CN1.
WIRING DIAGRAM
MV
VN
TW
TW
TS
FAN ASSISTED BOILERS
EV
VN
P
TP
TP
TS
BOILERS WITH
NATURAL DRAUGHT
IP version
EV1
EV2
VN
TW
TW
TS
3
9955042_H00.indd 3
15/07/2009 16.29.39
571 DBC
TECHNICAL DATA
STORAGE TEMPERATURE
-30 °C to +80 °C (-22 to 176 °F)
AMBIENT WORKING TEMPERATURE
-20 °C to +60 °C (-4 to 140 °F)
HUMIDITY
90 % max at 40 °C (not condensing)
SUPPLY VOLTAGE
120V (- 15 %, + 10 %, 50-60 Hz), 220-240V (- 15 %, + 10 %, 50-60 Hz)
POWER CONSUMPTION
20 VA
ELECTRICAL RATINGS
Gas valves: supply voltage, 1 A, cosϕ≥0.4
Fan: supply voltage, 0.5 A, cosϕ≥0.6
Alarm: volt free, 1 A, cosϕ=1
ELECTRICAL CONNECTIONS
High voltage probe: male fast-on connector 2.8 x 0.5 mm
Flame detection probe: male fast-on connector 4.8 x 0.8 mm
Other connections: Molex headers
Max. length of the I/O cables: 1 m
PROTECTION DEGREE
Standard IP 00
TIMING
Minimum waiting time Tw or purge time Tp: 1 ... 60 sec.
Maximum safety time Ts: 3 ... 120 sec.
Ignition attemps 1 ... 10
Relative interpurge time 0 ... 240 sec.
FLAME SENSING
Minimum flame current: 0.9 µA
Recommended flame current: > 3 times the minimum current
FUSING
Internal: 4 A fast non replaceable.
IGNITION
Ignition voltage: 15 KV at 30 pF load
Repetition rate: STANDARD 25 Hz (optional 4÷50 Hz @power supply 50 Hz)
Max. length of the cable: 1 m
Spark gap recommended: 2-4 mm
571 DBC DIMENSIONS [inch/mm]
6.42” / 163 mm
1.5” / 38 mm
4.25” / 108 mm
5.51” / 140 mm
SIT La Precisa S.p.A.
Viale dell’Industria 31-33
35129 PADOVA - ITALY
Tel. +39/049/829.31.11, Fax +39/049/807.00.93
www.sitgroup.it - e-mail: mkt@sitgroup.it
9955042_H00.indd 4
15/07/2009 16.29.39